Motor vehicles, including autonomous motor vehicles, may carry hydrocarbon fluids, evaporative gases of which pose environmental hazards. When the vehicle is exposed to solar energy loads, evaporation rates of such gases increase. Vehicles may carry on-board absorption devices that capture such evaporative gases. However, when vehicles are subjected to direct sunlight, the fuel of the vehicles may become elevated in temperature, and the capability of the on-board absorptions devices to contain such gases may be exceeded.